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Does Early Detection of Alzheimer's Make a Difference

Recent research suggests that Alzheimer's-related brain changes and biomarkers may be observable years or even decades before symptoms appear. But there's no way to prevent or stop the disease — so does it matter?

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WEDNESDAY, July 18, 2012 — High levels of a certain biomarker in the blood may be linked with an increased risk of developing Alzheimer’s disease, according to a new study in Neurology, the medical journal of the American Academy of Neurology.

Researchers from Johns Hopkins University measured the blood levels of serum ceramides, a fatty compound associated with inflammation, in 99 women between the ages of 70 and 79. They found that those who had the highest levels of the biomarker were 10 times more likely to develop Alzheimer’s over the next nine years than women with the lowest levels. Participants in the mid-level range were eight times more likely to develop the disease.

“Our study identifies this biomarker as a potential new target for treating or preventing Alzheimer’s disease,” said study author Michelle Mielke, PhD, now an epidemiologist with the Mayo Clinic in Rochester, Minn., in a press release for the study.

The key word, of course, is “potential.” Mielke’s evidence is far from conclusive, and even if further studies confirm the findings, a blood test that uses ceramides to diagnose the disease is still a long way off. But her research represents an important shift in how we approach Alzheimer’s: Scientists are increasingly looking at ways to find and possibly treat the disease before, not after, symptoms appear.

Changing How and When Alzheimer’s Is Diagnosed

Diagnosing Alzheimer’s largely relies on documenting cognitive decline over several months. There’s no definitive test or screening tool for the disease, so physicians first rule out other conditions, complete a full physical and neurological work-up, and then evaluate the patient’s medical history and mental status.

“We need a good marker for Alzheimer’s,” says Maria Carrillo, PhD, senior director of medical and scientific relations at the Alzheimer’s Association. “Even though we’re pretty good about detecting the disease with our current methodology, it’s a long and involved process. It can take six months to a year to get an accurate diagnosis. We need to utilize these technologies and techniques, like brain scans or cerebrospinal fluid tests or blood tests, to help clinicians.”

Mielke’s research is one step toward that goal. But there are other research teams, and other biomarkers. Australian scientists recently identified a set of 18 blood markers, mostly proteins, that distinguished Alzheimer's patients from healthy ones with 80 percent accuracy. They published their findings in the Archives of Neurology, alongside a report from U.S. researchers identifying a second set of Alzheimer’s-related biomarkers.

Alzheimer’s-related brain changes such as plaques and fluctuations in spinal fluid can be detected 25 years before the onset of symptoms, according to a separate study in the New England Journal of Medicine researched at the Washington University School of Medicine in St. Louis.

More research is needed before these methods can be used in a widespread clinical manner, but that’s not the only issue: No method of stopping or reversing the disease exists, so a diagnosis 10 to 15 years before the onset of symptoms might not improve the outcome. Certain drugs might help manage decline, but the end result would likely be the same.

The Benefits of Alzheimer’s Early Detection

The "findings are important, because identifying an accurate biomarker for early Alzheimer’s that requires little cost and inconvenience to a patient could help change our focus from treating the disease to preventing or delaying it,” said American Academy of Neurology member Valory Pavlik, PhD, in an accompanying editorial for the ceramides study.

“We know that biological markers have the potential to tell us that there might be changes in the body reflecting changes of Alzheimer’s disease maybe 10 to 15 years before symptoms occur,” the Alzheimer’s Association’s Dr. Carrillo explains. “If we can utilize that information in a clinical trial to give people an experimental medication 10 years prior to the onset of symptoms and actually delay the disease — or even prevent it — that would be great. That is our current vision.”

Meantime, diagnosing the disease early is still very valuable. You might not be able to change what’s going to happen to you, but you can better prepare yourself and your family for it.

“Earlier detection, even once symptoms are appearing, is always beneficial to the family,” Carrillo says. “For one thing, you can start on treatments that may potentially help with the symptoms of Alzheimer’s. And you can talk or work through family issues such as how you want care to be provided to you over the next coming years, what your finances are going to look like, what legal measures have to be taken into consideration as the disease progresses … There are a lot of things that can be done.”